Regional adiposity, specifically localization of an increased proportion of body fat in the abdominal region, is an independent risk factor for myocardial infarction, angina pectoris, stroke, noninsulin-dependent diabetes mellitus (NIDDM), and premature death. While causal mechanisms for these relationships have not been identified, excess abdominal fat has been associated with several of the risk factors for both cardiovascular disease and NIDDM, namely dyslipidemia, hyperinsulinemia, and glucose intolerance. Hormone replacement therapy has been found to prevent the accumulation of intra-abdominal fat observed in postmenopausal women. Although data are scarce, this and other observations support the theory that sex steroids affect the regulation of fat accumulation, mobilization, and distribution. The objectives of this project are: to evaluate the effects of hormone replacement therapy on regional fat distribution and characteristics; and to examine the relationships between fat distribution, risk factors for NIDDM and cardiovascular disease, and extent of coronary artery atherosclerosis in a well-characterized primate model, the female cynomolgus monkey.